The present invention relates to self starting orbiting fluid moving mechanisms and more specifically to an orbiting fluid mechanism possessing a very high fluid displacement to mechanism size, i.e. the displaced fluid per revolution is large compared to the volume of the mechanism which displaces this fluid. The object of this invention is to provide a fluid mechanism or engine which possesses a simplified mechanism yet which has certain porting advantages and a unique method of changing the displaced volume per revolution while the unit is operating.
These features are provided in order to enhance performance, reduce size, reduce friction losses and reduce cost. These features have the net effect of also reducing the energy required to operate the mechanism as a pump or to reduce the fluid energy required to operate the device as a fluid motor, internal combustion engine or fluid meter. The features herein disclosed could be used to advantage in devices built according to the disclosure of my prior U.S. Pat. No. 3,630,178.
The common prior art positive displacement fluid mechanisms possess relatively higher internal friction or resistance to flow for a given amount of fluid displaced. The present invention displaces approximately twice the amount of fluid as would be displaced by a rotary vane device of the same size, as well as resulting in decreased friction energy required to operate the device.
The rotary vane fluid mechanism has a ratio of displaced fluid to displacing mechanism of 0.35 to 0.50. The orbiting mechanism, with the configuration described herein has a ratio of displaced fluid to displacing mechanism of 0.8 and greater with about one half of the mechanism friction associated with the rotary vane device. This means the internal friction of the rotary vane fluid mechanism is about four times the orbiting fluid mechanism for the same amount of fluid displaced per shaft rotation. Typically, rotary vane fluid mechanisms exhibit high vane friction and leakage, low efficiency, and require a substantial pressure differential to operate; producing a relatively high lateral force on the rotor bearings resulting in higher wear and maintainability problems.
Another prior art fluid mechanism which has high friction and complexity is the axial and radial piston type fluid device. Self starting multi-piston (at least 3 or more pistons) mechanism are costly to fabricate, have high friction due to its many parts, require complicated valving and have a very low (0.2 to 0.3) fluid displacement-to-size ratio; although the piston type mechanisms do possess better sealing ability than the rotary vane fluid devices, they have relatively poor mechanical efficiency.
The many different types of gear mechanisms are also characterized by the problems of high friction, high leakage and low mechanical efficiency. The friction energy required to operate these units is normally higher for a given capacity than the rotary vane and piston types. In general, other prior art positive displacement, self starting fluid mechanisms require larger mechanisms with greater resistance to rotation for the same fluid displacement per shaft revolution as compared with the present invention.